Cough and hypereosinophilia due to FIP1L1-PDGFRA fusion gene with tyrosine kinase activity

Eosinophil-associated conditions, such as asthma and eosinophilic bronchitis, have been associated with chronic persistent cough, usually responding to corticosteroid therapy. This case study reports a case of persistent cough associated with gastro-oesophageal reflux (GOR) and hypereosinophilia. Treatment of GOR with proton pump inhibitors and fundoplication did not control the cough. However, high dose prednisolone, but not inhaled corticosteroids, did. The presence of the FIP1L1-PDGFRA fusion gene in myeloid cells was confirmed by fluorescence in situ hybridisation analysis using CHIC2 deletion as a surrogate marker. The cough and other disease features were subsequently suppressed by the tyrosine kinase inhibitor, imatinib. This is the first case of persistent cough caused by hypereosinophilic syndrome characterised by FIP1L1-PDGFRA fusion gene and aberrant tyrosine kinase activity.